Homocysteine is a recognized risk factor for atherosclerotic and thrombotic disease. Sickle cell anemia is a disease characterized by vaso-occlusive crises and thromboses. Therefore, we are investigating homocysteine levels in patients with sickle cell anemia, with a hypothesis that these patients may have hyperhomocysteinemia secondary to folate depletion from accelerated hematopoesis. Alternatively, their intake of folate and vitamins B12 and B6 may be insufficient to meet their needs, resulting in hyperhomocysteinemia. We are conducting a cross-sectional study of 70 children with homozygous sickle cell anemia and 30 healthy African-American children recruited from among the siblings of the patients. Each child has a fasting blood draw for measurement of serum homocysteine, serum folate, red blood cell folate, vitamins B12 and B6, hemoglobin, reticulocyte count, and creatinine. A nutritionist conducts a 24-hour dietary recall with each participant for assessment of protein and vitamin intake, and repeats this recall three more times over one year. Each participant has his or her medical history recorded, and a height and weight measurement. For our analysis, we are investigating whether the participants with sickle cell anemia have significantly different levels of homocysteine, folate, and vitamins from the healthy children. We are also investigating the relationship between homocysteine and the vitamins in the two groups, and whether the serum and plasma levels of vitamins vary differently based on intake in the two participant populations. We do not anticipate having sufficient power in this study to make strong conclusions regarding homocysteine and the participant's history of stroke or other thrombotic events. We anticipate that the results of this study will provide a basis for prospective studies of homocysteine and disease activity and also for interventions with vitamin supplementation aimed at lowering homocysteine levels in patients with sickle cell anemia.